fix(tools): recover provider-truncated tool names

[guustavomv]

Summary

Some providers emit tool calls with truncated tool names (e.g. Read → Rea, EnterPlanMode → EnterPlanMo). The executor failed those with No such tool available: <name>, forcing the model to retry or give up on tools like Read/EnterPlanMode.

• findToolByNameOrUniquePrefix (Tool.ts): when an exact name lookup fails, recover via prefix matching — only when the prefix is unambiguous, never for MCP tool names, and only for names ≥ 3 chars.
• Unique one-character completion: Rea recovers as Read even when the deferred ReadMcpResourceTool is also registered (a longer prefix match).
• Fallback after permission filtering (StreamingToolExecutor): recover truncated names against base tools when the definition was filtered out of the model's available set.
• Same recovery in runToolUse (toolExecution.ts) for the direct-execution path.

Also includes fix(tools): restore findToolByName import for interrupt handling — 7523ea3 swapped the import but getToolInterruptBehavior still calls findToolByName, which would throw a ReferenceError on the cancel/interrupt path.

Test plan

• bun test ./src/Tool.test.ts — 3 pass (new recovery cases)
• bun test ./src/services/tools/ — 12 pass across 4 files (Tool, StreamingToolExecutor tool pairing, toolExecution, tool result pairing)

Notes

• Deliberately does not guess MCP tool names or accept prefixes < 3 chars / ambiguous prefixes.
• Trade-off: a unique one-character completion can pick a shorter tool when the model meant a longer one; bounded and documented in code.