[Wasabules]

Stacked on #104, which is on #103. It will be retargeted to main once they are merged.

A rule that names an address loses its device when DHCP gives that device another address. SourceMatch.MACs lets a rule name devices by MAC instead.

What a rule takes

• A MAC, whole, in any spelling: aa:bb:cc:dd:ee:ff, AA-BB-CC-DD-EE-FF, aabb.ccdd.eeff.
• Or a pattern for one maker's devices: 04:03:12:*.
• Anything else is refused when the rule is saved (macEntry).

Local network only, and the UI says so

• The MAC comes from the neighbor table (feat(devices): MAC addresses and makers on the local network, and devices that moved #104). The reader asks it for the MAC of the address each message comes from, as the message arrives. The rule editor's preview and the re-reading of stored messages (feat(sources): read stored messages again with the rules #100) ask the same table.
• The table only knows this machine's own networks. Behind a router, every device arrives with the router's MAC, so the table is not asked there. An address with no MAC known (routed, or not in the table yet) does not match a rule that names MACs. A rule by MAC therefore never matches a device behind a router.
• The editor shows this in a highlighted note directly under the field. The user guide and the documentation page say the same.

Also

• When a rule names a single address whose MAC is known, the editor offers to name the MAC instead.
• The Devices tab also finds a device's rule by its MAC.
• The 8 languages, the user guide, the README and the documentation page are updated.

Tests

internal/sources:

• the same device at its address, then at its new address after a lease change;
• a maker's pattern;
• a device behind a router (no MAC) is never matched;
• the preview gives the same results;
• malformed entries are refused.

The UI was checked through the screenshot bridge: the field, the warning and the offer to name the MAC.

Checked: go vet (Windows, Linux), staticcheck, go test -race ./..., svelte-check --fail-on-warnings, npm test, npm run build, the docs' links.