refactor(llm-deepseek)!: rename the provider route to deepseek-official

The native adapter's route was named deepseek, colliding with pi-ai's
catalog provider of the same name, so the two DeepSeek paths could never
be mounted side by side. The web settings page needs both configurable at
once. Compositions, fixtures, goldens, scaffolding defaults, and docs all
move together (pre-release, no shim); TUI/session-query-spill/
missing-credential goldens re-recorded through their keyless refresh
modes because provider-name length shifts box padding and spill
truncation points.

examples/cordis-agent/cordis.yml

@@ -58,7 +58,7 @@
 - id: tui-agent
   name: '@deepseek-ai/dsh-tui-demo'
   config:
-    provider: deepseek
+    provider: deepseek-official
     model: deepseek-v4-pro
     resumeSessionId: !!js "typeof resumeSessionId === 'string' ? resumeSessionId : undefined"
     persistenceRoot: './.sessions'

examples/cordis-agent/tests/cordis-tools.e2e.ts

@@ -40,7 +40,7 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('cordis tools: a real model modif
   it('mounts a temporary status listener whose tagged output actually fires, then unmounts it', async () => {
     ctx = await cordisHarness()
     const log = vi.spyOn(console, 'log').mockImplementation(() => {})
-    const agent = ctx.agentLoop.create(SessionId('cordis-e2e-listener'), { provider: 'deepseek', model: 'deepseek-v4-flash' })
+    const agent = ctx.agentLoop.create(SessionId('cordis-e2e-listener'), { provider: 'deepseek-official', model: 'deepseek-v4-flash' })
 
     agent.followup(createUserMessage({
       content: [{
@@ -71,7 +71,7 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('cordis tools: a real model modif
 
   it('builds itself a reverse_text tool and actually calls it', async () => {
     ctx = await cordisHarness()
-    const agent = ctx.agentLoop.create(SessionId('cordis-e2e-selftool'), { provider: 'deepseek', model: 'deepseek-v4-flash' })
+    const agent = ctx.agentLoop.create(SessionId('cordis-e2e-selftool'), { provider: 'deepseek-official', model: 'deepseek-v4-flash' })
 
     agent.followup(createUserMessage({
       content: [{
@@ -119,7 +119,7 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('cordis tools: a real model modif
 
   it('composes two temporary Plugins through provide/inject, and unmounting the provider parks the consumer', async () => {
     ctx = await cordisHarness()
-    const agent = ctx.agentLoop.create(SessionId('cordis-e2e-compose'), { provider: 'deepseek', model: 'deepseek-v4-flash' })
+    const agent = ctx.agentLoop.create(SessionId('cordis-e2e-compose'), { provider: 'deepseek-official', model: 'deepseek-v4-flash' })
 
     agent.followup(createUserMessage({
       content: [{