docs: update connect and serve docs with review fixes

Document --share flag behavior (best-effort, warns on failure),
auto-sync hook, input validation rules (1MB content limit),
and duplicate registration rejection.

Signed-off-by: Murat Parlakisik <parlakisik@gmail.com>

Author: parlakisik

docs/cli/connect.md

@@ -72,6 +72,27 @@ Show hub connection state and entry statistics.
 ctx connect status
 ```
 
+## Automatic sharing
+
+Use `--share` on `ctx add` to write locally AND publish to the hub:
+
+```bash
+ctx add decision "Use UTC" --share \
+  --context "Need consistency" \
+  --rationale "Avoid timezone bugs" \
+  --consequence "UI does conversion"
+```
+
+If the hub is unreachable, the local write succeeds and a warning
+is printed. The `--share` flag is best-effort — it never blocks
+local context updates.
+
+## Auto-sync
+
+Once registered, the `check-hub-sync` hook automatically syncs
+new entries from the hub at the start of each session (daily
+throttled). No manual `ctx connect sync` needed.
+
 ## Shared files
 
 Entries from the hub are stored in `.context/shared/`:

docs/cli/serve.md

@@ -57,6 +57,14 @@ ctx serve --shared --port 9900 --peers host2:9901,host3:9901
 Raft is used only for leader election. Data replication uses
 sequence-based gRPC sync (append-only, no conflicts).
 
+### Validation
+
+The hub validates all published entries:
+- **Type** must be `decision`, `learning`, `convention`, or `task`
+- **ID** and **Origin** are required (non-empty)
+- **Content** max 1MB (text-only — decisions, learnings, conventions)
+- **Duplicate registration** is rejected (one token per project)
+
 ### Flags
 
 | Flag | Description |

internal/hub/entry_validate.go

@@ -12,6 +12,7 @@ import (
 )
 
 // maxContentLen is the maximum entry content size (1MB).
+// Entries are text-only (decisions, learnings, conventions).
 const maxContentLen = 1 << 20
 
 // allowedTypes is the set of valid entry types.