feat: register isphere file receive list tool

docs/superpowers/plans/2026-07-09-stage-c-log-backed-receive-messages-loop.md

@@ -1341,7 +1341,7 @@ Implemented and verified in this loop:
 - Output shape: `ok`, `mode`, `files`, `next_cursor`, and `audit`, aligned with `docs/mcp-core-tools-contract.md`.
 - Default empty source returns `ok: true`, `mode: "list"`, `files: []`.
 
-- [ ] **Step 1: Write failing MCP tool test**
+- [x] **Step 1: Write failing MCP tool test**
 
 Create `internal/tools/isphere_files_test.go` and run:
 
@@ -1351,15 +1351,15 @@ go test ./internal/tools -run TestISphereReceiveFilesToolReturnsLogBackedFiles -
 
 Expected initial failure: file receive tool registration does not exist.
 
-- [ ] **Step 2: Implement file tool registration**
+- [x] **Step 2: Implement file tool registration**
 
 Register `isphere_receive_files` with source injection for tests. Use `ListFilesFromMessages` and return a contract-shaped map with minimal audit metadata.
 
-- [ ] **Step 3: Wire server and verification**
+- [x] **Step 3: Wire server and verification**
 
 Register file receive in server construction. Update server tool-count tests and `scripts/verify-go-mcp.ps1` to expect eight tools and call `isphere_receive_files` against default empty source and synthetic configured file-transfer fixture.
 
-- [ ] **Step 4: Run full verification and commit**
+- [x] **Step 4: Run full verification and commit**
 
 Run:
 
@@ -1374,6 +1374,56 @@ Expected: all exit 0. Remove any generated root `isphere-mcp.exe` after build. C
 
 ---
 
+## Loop C14 Result
+
+Implemented and verified in this loop:
+
+- `internal/tools.RegisterISphereFileTools(server, source)` registers `isphere_receive_files` over the same receive-message source used by receive/contact/group tools.
+- `internal/mcpserver.NewServerWithReceiveSource` now exposes eight tools: four WinHelper tools plus `isphere_receive_messages`, `isphere_search_contacts`, `isphere_search_groups`, and `isphere_receive_files`.
+- `scripts/verify-go-mcp.ps1` now expects eight tools, allows the file-list read tool, and verifies default empty file results plus configured synthetic file-transfer extraction.
+- `isphere_receive_files` currently supports list mode only; download/cache mapping remains deferred because C12 found no message-to-cache hash link.
+- Verification completed for C14 with affected package tests and `powershell -NoProfile -ExecutionPolicy Bypass -File scripts/verify-go-mcp.ps1`; full verification is run again before commit.
+
+---
+
+## Loop C15: Send message source evidence precheck
+
+**Goal:** Before implementing `isphere_send_message`, identify the lowest-risk connector path and preview/audit shape from existing bridge/API, local data, UIA, or network evidence; do not implement write-capable behavior without a validated connector decision.
+
+**Planned files:**
+- Modify: `docs/source-discovery/capability-source-matrix.md`
+- Modify: `docs/current-status-card.md`
+- Modify: `docs/superpowers/plans/2026-07-09-stage-c-log-backed-receive-messages-loop.md`
+- Optionally create a focused source-discovery note under `docs/source-discovery/` if evidence is non-trivial.
+
+**Planned behavior:**
+- Inspect existing docs/contracts and committed helper/UIA/source-discovery artifacts for a send-message source candidate.
+- Rank candidate connector paths: existing bridge/API/local service, UIA draft/send path, network/protocol path, or blocked pending internal sandbox evidence.
+- If a safe connector exists, write C16 around preview-first `isphere_send_message` design or implementation.
+- If evidence is insufficient, mark send-message blocked on live/internal-sandbox connector evidence and choose the next read hardening node.
+
+- [ ] **Step 1: Inspect current source evidence for send-message connector candidates**
+
+Use committed docs and generated selector/source-discovery reports only. Do not infer a write path from unrelated read evidence.
+
+- [ ] **Step 2: Update matrix and next loop**
+
+Record whether send-message implementation can proceed, and rewrite C16 accordingly.
+
+- [ ] **Step 3: Verify docs-only change and commit**
+
+Run:
+
+```powershell
+git diff --check
+go test ./...
+powershell -NoProfile -ExecutionPolicy Bypass -File scripts/verify-go-mcp.ps1
+```
+
+Expected: all exit 0. Commit exact C15 paths only.
+
+---
+
 ## Self-Review
 
 - Spec coverage: the plan follows the user's cyclic requirement: plan first, implement one loop at a time, update the next loop after each result, and ask only on blockers.