Add a global search, and stop the sidebar logo squeezing

`GET /api/v1/search/` hands the client one flat index of everything worth
jumping to — flows and the nodes inside them, dashboards and the widgets on
them, panels, secrets, modules, workers and alert channels — and cmdk matches
it in the browser, so results narrow while typing without a round trip per
keystroke. A node hit is the one thing no list endpoint could answer: it opens
its flow with that node in focus.

The panel is reached from **Search** above Documentation in the sidebar, or
⌘K anywhere. The flow canvas palette moves to ⌘P, being the narrower of the two.

The panels dialog gains an address (`/dashboards?panels`) so a panel hit has
somewhere to land, and the sidebar logo gets `shrink-0`: the rail's width
animates while the logo is already back, and a flex item short of room is
squeezed rather than clipped.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016vGH7jqcXxWKP9wZFPyVdU

backend/fluksio/api/main.py

@@ -15,6 +15,7 @@ from fluksio.api.routes import (
     panels,
     private,
     runs,
+    search,
     secrets,
     users,
     utils,
@@ -38,6 +39,7 @@ api_router.include_router(observability.router)
 api_router.include_router(runs.router)
 api_router.include_router(artifacts.router)
 api_router.include_router(workers.router)
+api_router.include_router(search.router)
 # Remote access through a portal. Always mounted; with no enrolment the
 # endpoints only ever report that there is none.
 api_router.include_router(cloud.router)