feat: pin/unpin support for ring entries and static slots

[suyashkumar102]

closes #33

added pinned: bool to ClipEntry with serde(default) so existing saved data doesn't break.

eviction in push_dynamic now scans from the back and skips pinned entries instead of blindly popping. if everything is pinned the push is blocked entirely.

Cmd+Opt+P toggles pin on the current cursor entry, follows the same release-triggered pattern as C/V/X in chord.rs.

for static mode, trying to copy or cut into a pinned slot fails immediately with a notification — the content in that slot stays untouched.

pin state is persisted automatically since disk.rs already serialises the full ClipEntry struct.

[suyashkumar102]

@shaaravraghu I've opened the PR
Please add label gssoc:approved and other labels for type, quality and level for gssoc 2026

[shaaravraghu]

Static-mode storage is split into two disconnected sources of truth, so the new pinned/static behavior does not actually persist and can hide previously saved slots after startup. Engine now creates its own empty StaticSlotStore and all static operations read/write that private store (src/engine.rs (line 18), src/engine.rs (line 25), src/engine.rs (line 200), src/engine.rs (line 407)). But disk load/flush still only uses RamStore.static_slots (src/storage/disk.rs (line 41), src/storage/disk.rs (line 78)). That means:

static slots loaded from disk are never copied into Engine::static_store, so existing saved static entries can appear empty after restart;

new static copy/cut/delete/pin/encrypt/decrypt changes never mark RamStore dirty, so they are not flushed back to disk;

the PR message’s claim that static pin state “is persisted automatically” is false in the current implementation.

[shaaravraghu]

Both paste paths now paste even when clipboard sync fails, which can paste stale system clipboard contents instead of the selected entry. static_paste and dynamic_paste call self.sync_to_system_clipboard(...) and then unconditionally fire simulate_paste_delayed() (src/engine.rs (line 238), src/engine.rs (line 341)). The old helper only pasted on successful sync (src/engine.rs (line 129)). That is a real behavioral regression for any clipboard write failure.

[shaaravraghu]

@suyashkumar102 Please refine it.

[shaaravraghu]

Please sync fork to latest repo.

[shaaravraghu]

@suyashkumar102

[xthxr]

Please follow the plan related to the issue. If any additional files/ resources are added for checking functionality/ testing; please remove them. Please provide a clean commit. @suyashkumar102