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.

docs/query-language-reference.md

@@ -1,16 +1,16 @@
 # Query language reference
 
-Sentry has one query language for everything: filtering, free-text
+Cairn OBS has one query language for everything: filtering, free-text
 search, and aggregation, in a single query, against a single endpoint
-(`POST /query`), from a single query bar in the web UI or `sentryctl
+(`POST /query`), from a single query bar in the web UI or `cairnobsctl
 query` on the command line. You don't pick a "search mode" or a
-"reporting mode" first — you write one query, and Sentry figures out
+"reporting mode" first — you write one query, and Cairn OBS figures out
 which parts need ClickHouse, which parts need the full-text index, and
 combines them.
 
 If you already know Splunk's SPL, most of this will feel immediately
 familiar: a base search, piped through a sequence of processing stages.
-Sentry's language is a deliberately smaller subset — the operators
+Cairn OBS's language is a deliberately smaller subset — the operators
 people actually use day to day, not SPL's full surface area — plus raw
 SQL as an escape hatch for anything the pipe syntax doesn't (yet) cover.
 
@@ -67,7 +67,7 @@ timeout                              a single bare word
 message:"connection refused"         the same thing, explicit
 ```
 
-Free-text search is powered by Sentry's full-text index (Tantivy), which
+Free-text search is powered by Cairn OBS's full-text index (Tantivy), which
 supports phrase matching and wildcards:
 
 ```
@@ -92,7 +92,7 @@ what most people expect from a search bar:
 error timeout                        same as: error and timeout
 ```
 
-`or` works between free-text terms, and Sentry's full-text index handles
+`or` works between free-text terms, and Cairn OBS's full-text index handles
 it natively:
 
 ```
@@ -176,14 +176,14 @@ tail 50     last 50, chronologically
 
 ## Field mapping: what's a "real" column vs. an attribute
 
-Sentry's structured columns are `timestamp`, `host`, `service`,
+Cairn OBS's structured columns are `timestamp`, `host`, `service`,
 `severity`, `message`, and `record_id`. Anything else you reference by
 name — `status`, `latency_ms`, `winevt.event_id`, whatever your logs
 happen to carry — is looked up in the per-record attributes, which are
 always stored as text.
 
 This matters for comparisons: `status>=500` only makes sense as a number,
-so Sentry casts the attribute's text value to a number for you
+so Cairn OBS casts the attribute's text value to a number for you
 automatically when the value you're comparing against looks numeric.
 `status="unknown"` compares as text instead, since `"unknown"` isn't a
 number. You don't need to do anything differently — this happens based
@@ -212,7 +212,7 @@ directly, no pipe-syntax parsing involved:
 SELECT host, count(*) FROM logs WHERE service = 'api' GROUP BY host
 ```
 
-SELECT-only, single statement — Sentry allowlists this at the API level.
+SELECT-only, single statement — Cairn OBS allowlists this at the API level.
 Use this for anything the pipe syntax doesn't cover yet: window
 functions, `WITH` clauses, ClickHouse-specific functions, joins across
 other tables you've added, and so on. There's no performance penalty for
@@ -221,7 +221,7 @@ execution plan internally.
 
 ## Which syntax am I using?
 
-Sentry detects automatically: a query starting with `SELECT` runs as
+Cairn OBS detects automatically: a query starting with `SELECT` runs as
 SQL, anything else runs as the pipe syntax. This covers the overwhelming
 majority of real queries with no extra step. If you're writing a pipe
 query that happens to start with the literal word "select" as a search
@@ -237,7 +237,7 @@ detected next to the query box, with a dropdown to override it.
 
 ## Combining free-text search with aggregation
 
-This is the case that makes Sentry's query language more than "SQL with
+This is the case that makes Cairn OBS's query language more than "SQL with
 extra steps" — free text and aggregation, together, in one query:
 
 ```