Remove Eve tool approvals and keep Link purchase approval

[fmhall]

OpenInstinct paused with a generic “Approve tool call” prompt even after the user had requested the action. Remove all configured Eve tool-approval gates: Gmail sending, calendar creation, and the Link extension's spend-request creation.

The Link override retains the official authenticated execution path and SDK validation, always requests actual purchase approval in Link, and prevents disabling that approval through tool inputs. Update the agent's instructions to act on authorized requests and delegated choices within budget without redundant tool confirmations. Existing authentication and scheduled-worker capability restrictions remain.

Validation:

• pnpm check — all six tasks passed; 779 tests across 89 files.
• pnpm build and pnpm exec eve build — passed.
• Regression coverage verifies the tool policy, mandatory Link approval, preserved vendor validation, Google policies, root inventory, and loaded instructions.
• Independent review and one final re-review found no issues. No live emails, calendar writes, or purchases were performed.

The callback ownership repair is separate in #155.