fix: restore tab and diff context through jump history

docs/architecture.md

@@ -37,7 +37,7 @@ Frontends inspect `count()` for the optional pending numeric prefix; parsing, co
 Frontends inspect `sequence_pending()` for the cached display of a pending key sequence; prefix recognition, cancellation, and dispatch remain editor-owned. Symbolic leader routes and explicit key prefixes share the same binding storage and dispatcher; explicit prefixes do not change when the leader is reconfigured.
 Frontends inspect `g_pending()` for the built-in Normal/Visual `gt`/`gb` prefix and Normal-only `gf`. Document-edge motions share multi-target motion dispatch and viewport reveal, retaining Visual anchors and selection shape. Markdown following preflights links and headings before buffer/caret mutation; an unloaded target is validated/prepared once, while loaded targets use their current unsaved text. File identity and activation stay editor-owned.
 Frontends inspect `line_operator_pending()` for the optional Normal `d`/`c` prefix. Dedicated `dd`/`cc` actions project counted caret rows through existing linewise selection normalization, clipboard publication, and atomic range editing, without exposing a temporary Visual mode. Clipboard failures restore the original targets before returning. Repeat recipes retain the requested row count rather than the originally clamped range; change recipes share the existing Insert undo group. There is no general operator–motion parser.
-Editor-owned jump history is a bounded 100-location `VecDeque` of buffer IDs and grapheme cursors plus a current index, with no copied paths/text. Successful high-level navigation records departure/destination once; traversal uses unrecorded buffer activation and position placement, skips closed/clamped-duplicate locations, and truncates forward entries only on a distinct new jump. Session synchronization permanently invalidates pending LSP position requests after their source buffer/revision/caret/mode is left, so returning through history cannot revive an old definition reply.
+Editor-owned jump history is a bounded 100-location `VecDeque` of stable tab/pane identities, buffer IDs, grapheme cursors, and optional comparison identity/file/focus/binding metadata, with no copied paths/text. Successful high-level navigation records departure/destination once; traversal resolves a valid destination view before switching buffers, restores comparison binding and exact cursor visibility, and truncates forward entries only on a distinct new jump. Closed or replaced views fall back only to safe existing ordinary panes; history cannot resurrect a closed comparison or replace an unrelated one. Unavailable destinations are skipped without corrupting branch position. Session synchronization permanently invalidates pending LSP position requests after their source buffer/revision/caret/mode is left, so returning through history cannot revive an old definition reply.
 Frontends inspect `buffer_id()`, `buffer_count()`, `has_buffer(id)`, and the ascending-ID `buffers()` iterator of borrowed path/dirty/active metadata. Existing text, cursor, selection, search, and mode methods describe only the active buffer.
 Frontends inspect `tab_id()` for stable identity, `tab_index()` for display order, `tab_count()`, and `tab_buffer(index)` for borrowed title metadata. `pane_layout()` describes only the active tab; globally unique pane IDs keep inactive tabs' viewports alive. Documents remain unique across all tabs, while independent pane/buffer views are parked and restored without copying text.
 Frontends borrow `top_bar_config()` and `bottom_bar_config()` for validated ordered left/center/right segment groups and effective segment styles, and `label(name)` for session-wide custom values. The TUI owns terminal-cell widths, full-row center anchoring, clipping, and accent styling. Label effects carry only a name and plain text; they are global presentation updates, not buffer/revision-bound results or render callbacks.