fix(wallet): single-flight session setup

[LiranCohen]

Summary

• join concurrent identity sync setup by agent and DID
• join concurrent tenant registration by agent, DID, and endpoint while preserving retries after completion or failure
• avoid repeating first-connect post-session registration already performed by connectVault
• add focused concurrency and provider-flow regression tests

Test plan

• bun run lint -- --fix
• bun run lint (zero errors; existing warning baseline remains)
• bun run build
• bun run test (753 passed, 10 skipped)
• bun run test:coverage

[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🟢	Lines	68.86% (🎯 25%)	3452 / 5013
🟢	Statements	66.83% (🎯 25%)	3649 / 5460
🟢	Functions	65.23% (🎯 30%)	1051 / 1611
🟢	Branches	62.91% (🎯 29%)	2285 / 3632

File Coverage

File	Stmts	Branches	Functions	Lines	Uncovered Lines
Changed Files
src/enbox/identity-sync.ts	85.96%	68.75%	82.6%	85.96%	29, 57, 101-114, 148
src/enbox/provider.tsx	79.01%	49.35%	73.68%	81.95%	68, 81, 124, 182, 189-190, 197, 207, 215-216, 227, 233, 250-261, 267, 271, 282, 292, 335, 344, 359-364, 378, 402-407, 416-431, 440, 445-446
src/enbox/registration.ts	63.63%	54.05%	57.14%	65.88%	32, 37-102, 126, 136-140, 187, 201, 215-219, 242-248, 253
src/enbox/effect/keyed-single-flight.ts	100%	83.33%	100%	100%
src/enbox/mutations/identity-mutations.ts	73.82%	60.86%	70.93%	73.82%	59, 66, 88, 93, 98, 132-133, 150-160, 344-345, 393-398, 427-433, 441-450, 471-517, 591-596, 619-624, 636

Generated in workflow #419 for commit 39648ef by the Vitest Coverage Report Action

[LiranCohen]

Folded into #179 (feat/enbox-0.8.29 merged this branch unchanged) so the release adoption and the wallet-side single-flight fixes land — and are tested — together as the complete response to the sync-chattiness investigation. All 9 files and the new concurrency tests are in #179; 753 unit tests and 28 e2e pass on the combined branch against the 0.8.29 packages.