feat(navigation): gate editor activation capabilities - #400

Navigation MVP slice N5

Adds semantic, exact-context capability gates for document/sheet activation, object reveal/centering, and view fitting. On the bundled KiCad 10 protocol these operations return typed unsupported results and send no raw action.

Why this belongs in the MVP

Clients need an honest answer about activation and viewport behavior. Pretending that selection implies reveal, or routing through unstable action strings without active-context readback, would violate the Navigation MVP's safety contract.

Dependency

• Depends on feat(navigation): verify editor selection mutations #399 (N4 verified selection), which depends on feat(navigation): resolve exact editor targets #398, feat(navigation): observe exact editor selection #397, and feat(navigation): observe editor capabilities #396.
• Uses the typed Priority 0 IPC foundation through fix(ipc): bind operations to the requested board #390 and does not depend on draft fix(board): refuse stale locked file fallbacks #391.
• Tracks provisional public naming in Design Priority 1 semantic editor navigation MVP #395; this PR remains draft.

Behavior

• Accepts an explicit project, saved document, editor, and canonical schematic instance path.
• Resolves reveal/center object KIIIDs before any live request.
• Proves the exact open document/sheet and reads the running KiCad version/capability matrix.
• Reports activate_document, activate_sheet, reveal_object, center_object, or fit_view as typed unsupported_capability with the observed version when no stable command plus active-context readback exists.
• Stale objects and wrong/closed document or sheet contexts fail before any action.
• Sends only typed GetOpenDocuments and GetVersion probes; no RunAction, mouse, keyboard, or coordinate automation is exposed.

Intentionally unsupported

• KiCad 10 exact activation, reveal, center, and fit cannot report success because the bundled stable protocol provides neither the command nor the required active-context readback.
• A future version advertising a primitive still remains unsupported until Konnect has a version-gated semantic adapter and result-derived verification.

Verification

• cargo fmt --all -- --check
• cargo test -p konnect-core editor_navigation --lib — 15 passed
• cargo test -p konnect-ipc --test mock_server_test — 47 passed, 1 ignored
• cargo test -p konnect-core --lib — 946 passed, 9 ignored
• cargo test --workspace --all-targets — passed (live/environment-only tests remained ignored)
• cargo clippy --workspace --all-targets -- -D warnings
• xtask fix-doc-counts --check — 21 toolsets, 226 registered, 233 total
• git diff --check

Hermetic tests prove typed unsupported capability/version output, exact context probing, stale-object refusal before IPC, schematic activate_sheet classification, and the absence of any raw action request.

Remaining risks

• No real KiCad endpoint was available, so no live-GUI activation is claimed.
• Active editor/document/sheet state remains unobservable on the bundled KiCad 10 API and is never inferred from open-document order.
• Public naming and compatibility remain subject to Design Priority 1 semantic editor navigation MVP #395.