fix(sync): never put a filesystem path on the wire as ai.project

Several providers key a project by its sanitized absolute path
("-Users-me-Projects-app"), and sync shipped that verbatim as ai.project
on usage and attribution spans — contradicting docs/sync/README.md's
promise that file paths stay local. Confirmed on real exports.

One choke point after parseAllSessions maps project to the leaf directory
name before either wire path reads it; codeburn yield's local output is
untouched. Never-lose: usage span ids and commit attribution keys carry
no project (unchanged, no re-send); session attribution keys hash the
record, so each already-synced session re-emits once and the receiver
upserts by (org, trace) — replaced, not duplicated. Two directories with
the same leaf name now collapse to one wire project identity; that is
the documented contract, and git.repo still disambiguates.

src/sync/cli.ts

@@ -23,7 +23,7 @@ import {
 import { createCredentialStore } from './credentials.js'
 import { readSyncConfig, writeSyncConfig, deleteSyncConfig, updateLastSync } from './config.js'
 import { collectUnsentCalls, collectUnsentAttribution, sendBatches, sendAttributionBatches, batchCalls, MAX_PER_PUSH, MAX_ATTRIBUTION_PER_PUSH, type PushResult } from './push.js'
-import { batchAttributionItems } from './otlp.js'
+import { batchAttributionItems, wireProjectName } from './otlp.js'
 
 export function registerSyncCommands(program: Command): void {
   const sync = program
@@ -274,7 +274,8 @@ export function registerSyncCommands(program: Command): void {
           process.exit(1)
         }
         const { range } = getDateRange(period)
-        const projects = await parseAllSessions(range)
+        const projects = (await parseAllSessions(range))
+          .map(p => ({ ...p, project: wireProjectName(p.projectPath, p.project) }))
 
         // Flatten + filter against sent-ledger
         const { allCalls, unsent, held, frozen } = collectUnsentCalls(projects)

src/sync/otlp.ts

@@ -65,6 +65,16 @@ export function deriveTraceId(sessionId: string): string {
   return createHash('sha256').update(sessionId).digest('hex').slice(0, 32)
 }
 
+/**
+ * Wire-safe project identity: the leaf directory name. Several providers key a
+ * project by its sanitized absolute path ("-Users-me-Projects-app"), and
+ * docs/sync/README.md promises file paths stay local.
+ */
+export function wireProjectName(projectPath: string, fallback: string): string {
+  const normalized = projectPath.trim().replace(/\\/g, '/').replace(/\/+$/, '')
+  return normalized.split('/').filter(Boolean).pop() ?? fallback
+}
+
 // --- Timestamp conversion ---
 
 function toUnixNano(isoTimestamp: string): string {

tests/sync-attribution-cli.test.ts

@@ -10,7 +10,7 @@
 import { execFileSync } from 'node:child_process'
 import { mkdtemp, rm, writeFile } from 'node:fs/promises'
 import { tmpdir } from 'node:os'
-import { join } from 'node:path'
+import { basename, join } from 'node:path'
 
 import { describe, it, expect, beforeAll, afterAll, beforeEach, afterEach, vi } from 'vitest'
 import { Command } from 'commander'
@@ -154,4 +154,24 @@ describe('sync push --attribution (CLI level)', () => {
     const wire = JSON.stringify(idp.tracesRequests)
     expect(wire).toContain('github.com/acme/cli-widget')
   })
+
+  it('never puts a filesystem path on the wire as ai.project', async () => {
+    const now = Date.now()
+    const first = new Date(now - 90 * 60 * 1000).toISOString()
+    const last = new Date(now - 30 * 60 * 1000).toISOString()
+    const session = makeSession('cli-sess-1', first, last, [makeCall(`call-${now}`, first)])
+    parseAllSessionsMock.mockResolvedValue([
+      { project: `-${repoDir.replace(/^\//, '').replace(/\//g, '-')}`, projectPath: repoDir, sessions: [session] } as ProjectSummary,
+    ])
+    await runPush(['--attribution'])
+    const wire = JSON.stringify(idp.tracesRequests)
+    expect(wire).not.toContain(repoDir)                    // no absolute path
+    expect(wire).not.toContain(repoDir.replace(/\//g, '-')) // no slugified path
+    const projects = idp.tracesRequests.flatMap(r => (r.body as any).resourceSpans
+      .flatMap((rs: any) => rs.scopeSpans.flatMap((ss: any) => ss.spans))
+      .flatMap((s: any) => s.attributes.filter((a: any) => a.key === 'ai.project')
+        .map((a: any) => a.value.stringValue)))
+    expect(projects.length).toBeGreaterThanOrEqual(2)       // usage + attribution spans
+    expect(new Set(projects)).toEqual(new Set([basename(repoDir)]))
+  })
 })