Fix SMTP From-address fallback rejection; catalog card icon order; doc corrections

Mail sending fell back to a hardcoded noreply@theta42.com From address when
smtp.from wasn't set, which authenticated relays reject with "Sender is not
same as SMTP authenticate username" since no relay authorized this account
to send as that address. Falls back to smtp.user first now.

Also: catalog card titles now read name-then-icon instead of icon-then-name,
and a handful of docs corrections found in an accuracy pass (configuration.md
missing the OpenBao/live-config layer, plugins.md undercounting plugin types,
vault.md describing OpenBao dev-mode/root-token access that doesn't reflect
the real production setup, orphaned discovery.md/vault.md pages linked in,
README's required-groups list missing app_sso_directory_admin).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0113gCdnfSCuZr6xvPDxTo3D

docs/index.md

@@ -60,7 +60,10 @@ backend, that's the niche.
   run the pieces separately via `app_*` env config.
 - **Geo-Location Scaling** — built-in support for N-Way Multi-Master OpenLDAP [replication](replication.html) across physical sites.
 - **[Directory & Inventory](directory.html)** — map sites, hosts, and services as a graph with rich metadata (IP/MAC, OS/kernel, ports, git repos), auto-provisioned access groups, and automatic registration from theta-env and ldap-client. Drives directory-aware tools like the [SSH jump host](https://theta42.github.io/jump-host/).
+- **[Discovery](discovery.html)** — the catalog-vs-discovered distinction, how scanned assets are matched/merged into existing resources, and how a discovery gets promoted into the catalog (and becomes reachable through the jump host).
 - **[Theta Agent & Endpoint C2](agents.html)** — 2-way Go daemon (`theta-agent`) for real-time telemetry (CPU, RAM, Disk, ZFS, GPU), automated host discovery, SSSD/LDAP configuration, and local capability-controlled management operations.
+- **[Vault secrets](vault.html)** — an OpenBao-backed key-value store built into the UI, for stashing passwords/API keys/credentials with encryption and access control.
+- **[API tokens](concepts-api-tokens.html)** — self-service personal access tokens for calling the management API from scripts/CI without a browser session.
 
 ## Get it