feat: local display names for nodes

[gilindoesgit]

Local display names for nodes

Users can set a local display name for any node. That name is shown in the app instead of the device’s long/short name, and is stored only on the device (not sent over the mesh).

---

Summary

Storage	NodeDisplayNamePrefs (DataStore), keyed by node number
Scope	Node list, node detail, detail screen title
Edit entry points	Long-press node → “Set display name”; Node detail → “Display name” row

---

UI

• Node list – Each row shows the custom display name when set, otherwise the device long name.
• Long-press menu – “Set display name” (Edit icon) opens a dialog to set or clear the name.
• Node detail – Title shows the display name; a “Display name” row in the Details card is tappable to edit.
• Edit dialog – Text field (“Local name for this node”), Save, Cancel, and Clear display name.

---

Technical details

• Key: Display names are stored and looked up by node number (num), the unique node ID.
• Persistence: Single DataStore preference; map encoded as num\u0001name\u0002… with escaping for names containing delimiters.
• **New strings: set_display_name, display_name, display_name_hint, clear_display_name (default locale only in this PR).

---

Testing

• Unit tests: core/prefs/…/NodeDisplayNamePrefsTest.kt (defaults, set/get, clear, multiple nodes, trim).
• Run: ./gradlew :core:prefs:testDebugUnitTest

---

Checklist

• Display name keyed by node number only
• Shown in list and detail; editable from list context menu and detail row
• Clear display name restores device name
• No change to device identity or protocol; local-only

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.

---

Meshtastic Contributor seems not to be a GitHub user. You need a GitHub account to be able to sign the CLA. If you have already a GitHub account, please add the email address used for this commit to your account.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}