docs: describe the six-plugin layout after the split

README: replace the single-deft.so install instructions with the per-feature
plugin table (palette, switch, radial, acme, sam, plumb), a glob install loop,
and a note that the plugins cooperate by resolving each other's actions by
object name; refresh the layout tree (plugin/ gone, switch/ added, palette/ and
radial/ now hold their plugins) and mark milestones 5 and 6 DONE.

PLAN.md: add an architecture note at the top flagging the split and that the
design prose below refers to the former monolith as historical.

README.md

@@ -51,23 +51,41 @@ QT_QPA_PLATFORM=offscreen ./build/bin/test_fuzzyranker   # run the matcher tests
 ctest --test-dir build                                   # or via ctest
 ```
 
-## Install the plugin into Kate
+## Install the plugins into Kate
 
-The plugin builds to `build/bin/kf6/ktexteditor/deft.so`. Drop it where
-Kate scans for KTextEditor plugins (a user path on `QT_PLUGIN_PATH`):
+Deft is **one `.so` per feature**, not a monolith. The build produces six
+KTextEditor plugins under `build/bin/kf6/ktexteditor/`:
+
+| Plugin file      | Display name          | Feature |
+|------------------|-----------------------|---------|
+| `deft_palette.so`| `[deft:util] palette` | Command palette (`Alt+X` / M-x) over every window action + the `:`-verbs + the switchers, frecency-ranked |
+| `deft_switch.so` | `[deft:util] switch`  | Project **Go to File** (`Alt+P`) and **Go to Symbol** (`Alt+G`) |
+| `deft_radial.so` | `[deft:util] radial`  | Radial caret menu (`Alt+R` / right-mouse) |
+| `deft_acme.so`   | `[deft:nineify] acme` | Acme editing gestures (line keys, pair selection, mouse chords) |
+| `deft_sam.so`    | `[deft:nineify] sam`  | `sam`-style structural regular expressions |
+| `deft_plumb.so`  | `[deft:nineify] plumb`| Plan 9 plumber (open under cursor) |
+
+Drop whichever features you want where Kate scans for KTextEditor plugins (a
+user path on `QT_PLUGIN_PATH`):
 
 ```sh
-install -D build/bin/kf6/ktexteditor/deft.so \
-  ~/.local/lib/x86_64-linux-gnu/qt6/plugins/kf6/ktexteditor/deft.so
+for so in build/bin/kf6/ktexteditor/deft_*.so; do
+  install -D "$so" ~/.local/lib/x86_64-linux-gnu/qt6/plugins/kf6/ktexteditor/"$(basename "$so")"
+done
 ```
 
-Then in Kate: Settings → Configure Kate → Plugins → enable
-**Deft**. Press **Alt+X** (M-x) to open the command palette;
-type to filter, Enter or click to run. Open the editing **radial menu** either
-by pressing **Alt+R** (opens at the caret) or by **pressing the right mouse
-button** in the editor (opens at the pointer; the normal context menu is
-suppressed while this is enabled). Move toward a slice and release — or click;
-a branch slice (marked ▸) opens a submenu, the centre hub goes back/cancels.
+Then in Kate: Settings → Configure Kate → Plugins → enable each **`[deft:…]`**
+plugin you installed. Press **Alt+X** (M-x) to open the command palette; type to
+filter, Enter or click to run. Open the editing **radial menu** either by
+pressing **Alt+R** (opens at the caret) or by **pressing the right mouse button**
+in the editor (opens at the pointer; the normal context menu is suppressed while
+this is enabled). Move toward a slice and release — or click; a branch slice
+(marked ▸) opens a submenu, the centre hub goes back/cancels.
+
+The plugins cooperate but do not depend on one another: palette's "Go to
+File/Symbol" entries and radial's launcher slices resolve `switch`'s actions by
+object name at runtime, so each `.so` works on its own and simply gains those
+entry points when its sibling is also enabled.
 
 ## Status
 
@@ -79,16 +97,26 @@ See [docs/PLAN.md](docs/PLAN.md) for the full roadmap.
 - **Milestone 2 — custom palette widget: DONE.** `PaletteModel` +
   `PaletteWidget` (frameless popup, live filtering, highlighted matches,
   keyboard + mouse activation). 10 model unit tests, all green.
-- Milestone 3 — KTextEditor plugin + M-x: **DONE.** Loadable `deft.so`;
-  `Alt+X` opens the palette over every action in the window's GUI clients.
+- Milestone 3 — KTextEditor plugin + M-x: **DONE.** `Alt+X` opens the palette
+  over every action in the window's GUI clients.
 - Milestone 4 — radial caret menu: **DONE (first increment).** Multi-level
   radial menu at the caret (`Alt+R`) or at the pointer via a **right-mouse
   gesture**, mouse-driven selection, config tree with per-radial key + mouse
   triggers. Free-form stroke gestures next.
-- Milestone 5 — command vocabulary + project-as-directory + switchers: next.
+- Milestone 5 — command vocabulary + project-as-directory + switchers: **DONE.**
+  `:`-verb pack, project file (`Alt+P`) and symbol (`Alt+G`) switchers over an
+  async, cached index.
+- Milestone 6 — one `.so` per feature: **DONE.** The monolithic plugin is split
+  into six independent KTextEditor plugins (`palette`, `switch`, `radial`,
+  `acme`, `sam`, `plumb`), tagged `[deft:util]` / `[deft:nineify]`, cooperating
+  by resolving each other's actions by object name at runtime.
 
 ## Layout
 
+Shared building blocks are static libraries (`fuzzy`, `palette`, `project`,
+`commands`, …); each feature is a self-contained KTextEditor plugin that links
+the libraries it needs.
+
 ```
 CMakeLists.txt            top-level KF6/Qt6/ECM project
 src/
@@ -98,20 +126,33 @@ src/
   palette/
     palettemodel.{h,cpp}  ranked, filterable list model (headless)
     palettewidget.{h,cpp} frameless command-palette popup
-    test_palettemodel.cpp QTest suite
+    frecencystore.{h,cpp} persisted frecency ranking
+    paletteplugin.{h,cpp} [deft:util] palette — M-x, :-verbs, switcher doors
+    paletteplugin.json    plugin metadata
+    test_*.cpp            QTest suites
+  switch/
+    switchplugin.{h,cpp}  [deft:util] switch — Go to File (Alt+P) / Symbol (Alt+G)
+    switchplugin.json     plugin metadata
   radial/
     radialmodel.{h,cpp}   radial tree + hit-test geometry (headless)
     radialmenu.{h,cpp}    frameless multi-level radial widget
     radialconfig.{h,cpp}  JSON → radial tree + built-in default
-    test_radialmodel.cpp  QTest suite
-    test_radialconfig.cpp QTest suite
+    radialplugin.{h,cpp}  [deft:util] radial — caret menu plugin
+    radialplugin.json     plugin metadata
+    test_*.cpp            QTest suites
   commands/
     texttransforms.{h,cpp}  pure text transforms (headless)
-    olliecommands.{h,cpp}   ":"-verb KTextEditor::Command pack
-    test_texttransforms.cpp QTest suite
-  plugin/
-    ollieplugin.{h,cpp}   KTextEditor::Plugin + M-x + radial wiring
-    ollieplugin.json      plugin metadata
+    olliecommands.{h,cpp}   ":"-verb KTextEditor::Command pack (used by palette)
+    test_*.cpp              QTest suites
+  project/
+    projectindex / symbolindex / projectindexer / kateprojectbridge
+                          async, cached file & symbol index (used by switch)
+  acme/
+    acmeplugin.{h,cpp,json} [deft:nineify] acme — editing gestures
+  sam/
+    sam* + samplugin.{h,cpp,json} [deft:nineify] sam — structural regexps
+  plumb/
+    plumb* + plumbplugin  [deft:nineify] plumb — Plan 9 plumber
 docs/
   PLAN.md                 goal, constraints, roadmap
 ```

docs/PLAN.md

@@ -1,5 +1,18 @@
 # Plan — kate-custom
 
+> **Architecture note (current):** The suite has been split into **one `.so` per
+> feature** — `deft_palette`, `deft_switch`, `deft_radial`, `deft_acme`,
+> `deft_sam`, `deft_plumb` — each a standalone `KTextEditor::Plugin` tagged
+> `[deft:util]` / `[deft:nineify]`. See the README's plugin table for the
+> current layout. The design prose below predates that split and still refers to
+> the former monolith (`OlliePlugin` / `OllieView`, a single `olliepalette.so`,
+> and the `olliepalette/` config dir); read those names as historical. In the
+> split suite the palette plugin owns the M-x launcher and the `:`-verbs, the
+> switch plugin owns the file/symbol switchers and the project index, each plugin
+> keeps its own `FrecencyStore` file under `deft/`, and the doors cooperate by
+> resolving each other's actions by object name at runtime rather than by direct
+> calls or link dependencies.
+
 ## Goal
 
 Build a suite of Kate plugins that make the editor usable without menus, tuned