rename: the desktop is Inkwell — crates, Tauri identity, data move, packaging

Step 3 of milestone 481 (Scribe note 5071: a full rename).

- crates thoughtsync-{core,desktop,ffi,uniffi-bindgen} → inkwell-*, the
  Cargo.lock entries moved to match (checked with `cargo metadata --locked`)
- Tauri: productName "Inkwell", identifier com.fabledsword.inkwell, binary
  `inkwell`, updater feed on bvandeusen/inkwell, store file inkwell.db
- client agent inkwell-desktop, headers X-Inkwell-Client/-Protocol (the server
  reads neither), capture event inkwell://captured, display-version env
- .deb: conflicts + replaces thought-sync, so the updater's install retires the
  old package instead of colliding on it. kebab-case("Inkwell") is `inkwell`, so
  the package name finally matches the command and verify.sh now asserts it
- pacman: inkwell, conflicting with and replacing thoughtsync and
  thoughtsync-desktop
- AppImage ~/Applications/Inkwell.AppImage, menu entry inkwell.desktop,
  installer, release titles, desktop asset names in fetch-clients.sh

The one shim, chosen by the operator because it is the only copy of a
local-first user's notes: crossover.rs moves the old
com.fabledsword.thoughtsync app-data dir's contents into the new one on startup,
before the store opens, renaming thoughtsync.db and its -wal/-shm with it. It
skips when the new dir already has a store, and anything already in the new dir
wins (the installer writes its channel marker there first). Tested.

Android's Kotlin side (package, applicationId, uniffi class) is step 4. Its
release asset names stay thoughtsync.* until then.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

android/ffi/src/lib.rs

@@ -1,4 +1,4 @@
-//! uniffi bindings: `thoughtsync-core` as seen from Kotlin.
+//! uniffi bindings: `inkwell-core` as seen from Kotlin.
 //!
 //! This crate is to Android what `desktop/src-tauri/src/commands/` is to the desktop
 //! — a thin shim over the shared core, holding no logic of its own. If something here
@@ -38,9 +38,9 @@ pub mod models;
 use std::path::PathBuf;
 use std::sync::Arc;
 
-use thoughtsync_core::local::{self, Db};
-use thoughtsync_core::sync::blobs::BlobStore;
-use thoughtsync_core::sync::{client, compat, engine, push, state};
+use inkwell_core::local::{self, Db};
+use inkwell_core::sync::blobs::BlobStore;
+use inkwell_core::sync::{client, compat, engine, push, state};
 
 use models::{
     patch_from, BodyItem, BodyTag, ClientUpdate, Identity, Label, Note, NoteDraft, NoteEdit,
@@ -120,14 +120,14 @@ impl ThoughtSync {
     ///
     /// `data_dir` comes from Kotlin because only Android knows where its app-private
     /// storage is; the core must not guess at a platform path. The layout inside is
-    /// the core's business and matches the desktop's exactly — `thoughtsync.db` and
+    /// the core's business and matches the desktop's exactly — `inkwell.db` and
     /// `blobs/` — so a store is readable by any client that opens it.
     #[uniffi::constructor]
     pub fn new(data_dir: String) -> Result<Arc<Self>, CoreError> {
         let dir = PathBuf::from(data_dir);
         std::fs::create_dir_all(&dir).map_err(CoreError::store)?;
 
-        let db = local::open(&dir.join("thoughtsync.db")).map_err(CoreError::store)?;
+        let db = local::open(&dir.join("inkwell.db")).map_err(CoreError::store)?;
         log::info!("local store ready — {}", local::summary(&db));
 
         let blobs = BlobStore::new(dir.join("blobs")).map_err(CoreError::store)?;
@@ -583,7 +583,7 @@ pub fn checklist_render(text: String, checked: bool) -> String {
 ///
 /// Android has to say so because the core cannot: the same crate is compiled into
 /// the desktop app, and it used to announce every phone in the field as
-/// `thoughtsync-desktop` carrying the CORE crate's version — a number no build
+/// `inkwell-desktop` carrying the CORE crate's version — a number no build
 /// stamps and nobody has seen. The honest value is the installed package's own
 /// `versionName`, which is what Kotlin passes here.
 ///
@@ -680,7 +680,7 @@ mod tests {
         use std::sync::atomic::{AtomicU32, Ordering};
         static NEXT: AtomicU32 = AtomicU32::new(0);
         let dir = std::env::temp_dir().join(format!(
-            "thoughtsync-ffi-{}-{}",
+            "inkwell-ffi-{}-{}",
             std::process::id(),
             NEXT.fetch_add(1, Ordering::Relaxed)
         ));