docs(indexes): skim layer skimmable, one undescribed entry described

An index is the skim layer: its entries decide whether a reader opens the page, so an entry
that runs 250 characters is a paragraph wearing a bullet. Four entries in `tools/index.md`
(`dotfiles-deploy`, `packages`, `pcie-probe`, `remote-job`) now say what the page is for in one
line and let the page carry the detail — which is the whole argument for progressive disclosure
having an index at all.

`engineering/infra/index.md` pointed at `../sdlc.md` with no description at all; it now carries
the one from that page's frontmatter, like its four siblings.

Refs #64

omp-docs/tools/index.md

@@ -9,7 +9,7 @@ Configuration guides and reference material for installed software. Each tool ha
 * [applications](applications.md) — Default userspace applications on CachyOS with Niri — browsers, editor, terminal, file manager, audio, screenshots, gaming.
 * [cachyos](cachyos.md) — Arch-based rolling release with performance-optimized kernels, repositories, and gaming stack. Running on the workstation.
 * [comfyui](comfyui/index.md) — Node-based AI image generation engine on dankclaw. FLUX.2 klein 4B, CPU backend, systemd managed.
-* [dotfiles-deploy](dotfiles-deploy.md) — How `dotfiles/` packages become live config: `deploy.sh` modes, host override packages, and the tier's hard-won laws, from media and generated theme output to systemd enable/start semantics, dconf dumps, and idle-lock watcher triage.
+* [dotfiles-deploy](dotfiles-deploy.md) — How `dotfiles/` packages become live config: `deploy.sh` modes, host overrides, and the tier's laws.
 * [ghostty](ghostty/index.md) — GPU-accelerated terminal emulator with extensive configuration, keybindings, and shaders.
 * [gitea](gitea/index.md) — Private Git hosting on dankclaw. Quadlet-managed containers: Gitea, PostgreSQL, Caddy.
 * [handy](handy.md) — Offline speech-to-text transcription with WebKitGTK backend and Tauri v2 UI.
@@ -19,9 +19,9 @@ Configuration guides and reference material for installed software. Each tool ha
 * [neovim](neovim.md) — Two editors in one binary: vanilla `nvim` for quick edits and the `lazyvim` NVIM_APPNAME profile, with the base16 wallpaper-palette hook and fresh-box install.
 * [niri](niri/index.md) — Scrollable-tiling Wayland compositor — configuration, keybindings, and architecture for the workstation.
 * [noctalia-shell](noctalia-shell.md) — Native desktop environment for Niri — launcher, control center, settings, lock screen, session menu, hotkey overlay, media controls, and system management.
-* [packages](packages.md) — `packages/*.pkgs` desired state and the two tools that keep a machine and its manifest agreeing: `install.sh` installs the delta, `pkg-inventory.sh` reports what the machine has outgrown.
-* [pcie-probe](pcie-probe.md) — HIP probes that separate PCIe link bandwidth from the engine's read path at the expert-slab size, and the refuse-by-default guard against benchmarking beside a live service.
-* [remote-job](remote-job.md) — Detached job runner for `ssh` work: completion sentinels on the host replace the `tail -f | sed -n /ready/q` pattern that reported success on jobs that never finished.
+* [packages](packages.md) — `packages/*.pkgs` desired state, plus `install.sh` (installs the delta) and `pkg-inventory.sh` (reports drift).
+* [pcie-probe](pcie-probe.md) — HIP probes separating PCIe link bandwidth from the engine's read path; refuses to run beside a live service.
+* [remote-job](remote-job.md) — Detached `ssh` jobs with completion sentinels; replaces the `tail -f | sed` readiness pattern that lied.
 * [tmux](tmux.md) — Terminal multiplexer configuration, extended-keys setup, keyboard input best practices, and reload/restart procedures.
 
 ## Adding a New Tool