[P1][WS-03] Trusted control surfaces and task centre

Programme: #1
Epic: #16

## Objective
Provide trusted, non-spoofable controls for identity, inference mode, task execution, approvals and human takeover.

## Scope
- Persistent trusted chrome for active profile/account, inference mode, execution location and active tasks.
- Task centre showing lifecycle state, budget, provider, accessed resources, current step, failures and receipts.
- Pause, stop, take-over, approve, reject, revise and resume controls.
- Trusted confirmation surfaces rendered outside generated/provider content.
- Explicit state labels for proposed, attempted, committed, verified, failed and needs-reconciliation.
- Notification/approval queue hooks.

## Security rules
- Generated UI/web content/provider UI cannot render or overlay a substitute trusted approval surface.
- Stop revokes future authority but cannot falsely claim already-committed external effects were undone.
- Account/provider/model location is visible before consequential work.

## Acceptance criteria
- [ ] Generated/provider content cannot impersonate trusted approvals or global stop controls.
- [ ] User can stop/cancel while inference/browser workers are stalled.
- [ ] Attempted vs externally verified completion is visibly distinct.
- [ ] Take-over revokes or pauses the appropriate execution lease before user control begins.
- [ ] Task centre links to relevant evidence, actions, policy decisions and receipts.
- [ ] Execution location (`this device`, isolated session, home worker, cloud/provider) is visible.

## Dependencies
- WS-01
- SEC-02
- CORE-03

**First phase:** P1
**Maturity target:** P4
**Owner:** workspace-ui-data

## Task issues
- [ ] #328 `WS-03.T01` — Define trusted surface ownership
- [ ] #329 `WS-03.T02` — Build task projections and outcome labels
- [ ] #330 `WS-03.T03` — Implement pause, stop and takeover controls
- [ ] #331 `WS-03.T04` — Render exact approval proposals
- [ ] #332 `WS-03.T05` — Show inference mode and execution location
- [ ] #333 `WS-03.T06` — Implement audit and receipt drill-down
- [ ] #334 `WS-03.T07` — Handle stale notifications and concurrent decisions
- [ ] #335 `WS-03.T08` — Qualify trusted-control accessibility and stress

No files, tests, or entry points are named. Start by reading the linked dependencies and task issues #328–#335, then use the acceptance criteria to define completion: trusted controls must resist spoofing, support interruption and takeover, distinguish outcomes, expose execution location, and link evidence and receipts.

Written by the indexing model from the issue text.