fix(accounts): improve shared-context editing and discoverability

docs/session-sharing-technical-analysis.md

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+# Session Sharing Technical Analysis
+
+Last Updated: 2026-02-26
+
+## Summary
+
+CCS supports practical cross-account continuity by sharing workspace context files between selected accounts, while keeping credentials isolated per account.
+
+This is implemented as a context policy per account:
+
+- `isolated` (default): account keeps its own workspace context
+- `shared`: account workspace context is linked to a shared context group
+
+## Why This Is Safe Enough
+
+CCS only shares workspace context paths (project/session context files). It does **not** merge or copy authentication credentials between accounts.
+
+Credential storage remains per account instance.
+
+## Implementation Model
+
+Account metadata is stored in `~/.ccs/config.yaml`:
+
+```yaml
+accounts:
+  work:
+    created: "2026-02-24T00:00:00.000Z"
+    last_used: null
+    context_mode: "shared"
+    context_group: "team-alpha"
+```
+
+Rules:
+
+- `context_mode` must be `isolated` or `shared`
+- `context_group` is required when `context_mode=shared`
+- group normalization: trim, lowercase, internal spaces -> `-`
+- group must start with a letter and only include `[a-zA-Z0-9_-]`
+- max length: `64`
+
+## User Workflows
+
+### New account with shared context
+
+```bash
+ccs auth create work2 --share-context
+ccs auth create backup --context-group sprint-a
+```
+
+### Existing account
+
+- Open `ccs config`
+- Go to `Accounts`
+- Click the pencil icon (`Edit Context`)
+- Choose `isolated` or `shared` and set group
+
+No account recreation required for this workflow.
+
+## Current Limitations
+
+- Shared context is local filesystem sharing. It does not bypass remote provider permission models.
+- Session continuity still depends on what the upstream tool/provider stores and allows.
+- Context sharing should only be enabled for accounts you intentionally trust to share workspace history.
+
+## Validation Checklist
+
+- Confirm account row shows `shared (<group>)` in Dashboard Accounts table
+- Switch between accounts in the same group and verify workspace continuity
+- Run `ccs doctor` if symlink/context health looks inconsistent
+