Rebrand: Sentry -> Cairn OBS

Full rebrand across cosmetic branding, code identifiers, and
infrastructure/data-plane naming, using the supplied Cairn OBS logo
package. Cosmetic: favicon/logo swap (also closes a stale license-audit
finding -- the old favicon was SvelteKit's unreplaced scaffold logo),
new centered welcome landing page, larger/legible sidebar logo, page
titles, CLAUDE.md/README/docs prose.

Code identifiers: Go module path github.com/sentry/sentry ->
github.com/cairnobs/cairnobs across all 13 modules and ~91 files (protoc
regenerated); Rust crates sentry-agent/sentry-parser/sentry-search ->
cairnobs-*; CLI sentryctl -> cairnobsctl; Terraform provider fully
renamed (sentry_dashboard etc. -> cairnobs_dashboard, provider type,
env vars); every session/auth cookie name; agent config paths and
Windows service identity.

Deliberately preserved: the gRPC wire protocol's protobuf packages
(sentry.logs.v1, sentry.agent.v1) and their Go import directory
(proto/sentry/...) -- renaming the wire-level package would break every
currently-deployed agent binary (confirmed two real hosts, including
mail.inbuxa.com, are actively streaming through this exact contract)
until rebuilt and redeployed in lockstep with an ingest cutover. Only
the Go module path wrapping the generated code changes.

Infrastructure: every docker-compose container name (root and three
component-level compose files); the Helm chart (directory, Chart.yaml,
named-template helpers, all templates, values.yaml image repos);
Kubernetes Operator (CRD group sentry.io -> cairnobs.io, both CRD YAML
files, Go identifiers, RBAC markers); the coupled enterprise/tenantcrd
package. Caught and fixed real path-coupling bugs along the way: the
Helm chart's search/ingest volume mounts and the dev-only-credential
detection constant vs. docker-compose.yml's literal values had to move
together or a security warning would have silently stopped firing.

Data plane: Postgres database sentry_metadata -> cairnobs_metadata and
role sentry -> cairnobs; ClickHouse database sentry -> cairnobs; Kafka
topic sentry.logs.raw -> cairnobs.logs.raw and its consumer groups.
Source-level defaults, docker-compose.yml, and every migrate.sh/
provision script default updated together; already-applied migration
files left untouched per this repo's immutable-migration convention.

Verified at every layer: all 13 Go modules build/vet/test clean, both
Rust workspaces (agent, search) build/clippy/test clean, npm run check/
build clean, docker compose config validates on all four compose files.
Live-verified against a real docker stack multiple times through this
work, including a final fresh-volume run confirming the actual renamed
Postgres database/role, ClickHouse database, and Kafka topic all work
end to end with a real login and query, zero console errors.

cli/README.md

@@ -1,20 +1,20 @@
-# sentryctl
+# cairnobsctl
 
-Sentry's control CLI.
+Cairn OBS's control CLI.
 
 ```sh
-sentryctl ping                              # checks http://localhost:8080/healthz
-sentryctl ping --api http://api.internal:8080
-SENTRYCTL_API_URL=http://api.internal:8080 sentryctl ping
+cairnobsctl ping                              # checks http://localhost:8080/healthz
+cairnobsctl ping --api http://api.internal:8080
+CAIRNOBSCTL_API_URL=http://api.internal:8080 cairnobsctl ping
 ```
 
 Exits 0 and prints `ok` if `/api`'s `/healthz` responds 200; exits 1 with an
 error on `stderr` otherwise.
 
 ```sh
-sentryctl query 'service=api | where status>=500 | stats count by host'
-sentryctl query 'SELECT * FROM logs LIMIT 10' --language sql
-sentryctl query 'message:"connection refused"' --json
+cairnobsctl query 'service=api | where status>=500 | stats count by host'
+cairnobsctl query 'SELECT * FROM logs LIMIT 10' --language sql
+cairnobsctl query 'message:"connection refused"' --json
 ```
 
 Quote the query in your shell — pipe syntax uses `|`, which your shell
@@ -27,17 +27,17 @@ Prints a table by default (stdlib `text/tabwriter`, no new dependency);
 `--json` prints the raw `{columns, rows}` response instead.
 
 ```sh
-sentryctl dashboards list
-sentryctl dashboards get <id>
-sentryctl dashboards apply dashboard.json    # imports a dashboard exported via the web UI's "Export JSON" button
+cairnobsctl dashboards list
+cairnobsctl dashboards get <id>
+cairnobsctl dashboards apply dashboard.json    # imports a dashboard exported via the web UI's "Export JSON" button
 
-sentryctl dashboards permissions list <dashboard-id>
-sentryctl dashboards permissions grant <dashboard-id> <user-id> viewer|editor
-sentryctl dashboards permissions revoke <dashboard-id> <user-id>
+cairnobsctl dashboards permissions list <dashboard-id>
+cairnobsctl dashboards permissions grant <dashboard-id> <user-id> viewer|editor
+cairnobsctl dashboards permissions revoke <dashboard-id> <user-id>
 
-sentryctl alerts list
-sentryctl alerts get <id>
-sentryctl alerts apply rule.json             # creates a rule from a JSON file shaped like POST /rules's body
+cairnobsctl alerts list
+cairnobsctl alerts get <id>
+cairnobsctl alerts apply rule.json             # creates a rule from a JSON file shaped like POST /rules's body
 ```
 
 `dashboards permissions` is Phase 4's per-resource dashboard grant
@@ -51,7 +51,7 @@ CLI bug.
 
 `dashboards` talks to `/api` (`--api`, same override as `query`/`ping`).
 `alerts` talks to `/alerting`, a separate service with its own base URL
-(`--alerting-api`, or `$SENTRYCTL_ALERTING_API_URL`, default
+(`--alerting-api`, or `$CAIRNOBSCTL_ALERTING_API_URL`, default
 `http://localhost:8081`) — see `/docs/phase-3-alerting-design.md`'s
 component boundary for why alerting isn't just another `/api` route.
 `apply` in both cases sends the file's JSON as-is to the corresponding
@@ -78,5 +78,5 @@ go test ./...
 ```
 
 ```sh
-docker build -f Dockerfile -t sentryctl .   # context is cli/, not the repo root
+docker build -f Dockerfile -t cairnobsctl .   # context is cli/, not the repo root
 ```