Standardize naming conventions across docs and source

Rename NodeId to NodeAddr and npub to pubkey throughout documentation
and source code for consistency with the established identity model.
Add FIPS API vs IPv6 adapter overview to session protocol document.
Add transport address terminology note to wire protocol document.

docs/design/spanning-tree-dynamics.md

@@ -64,7 +64,7 @@ maintains roughly 50 TreeState entries, not 1000.
 
 ### Root Election
 
-The root is deterministic: the node with the lexicographically smallest node_id
+The root is deterministic: the node with the lexicographically smallest node_addr
 among all reachable nodes. No explicit election protocol exists—each node
 independently derives the same answer from its local TreeState.
 
@@ -86,7 +86,7 @@ When a node starts with no peers, it bootstraps as a single-node network.
 ```
 Time T0: Node A starts
 ├── Generates or loads keypair (npub_A, nsec_A)
-├── Computes node_id_A = SHA-256(npub_A)
+├── Computes node_addr_A = SHA-256(npub_A)
 ├── Initializes empty TreeState
 ├── Sets parent = self (A is its own root)
 ├── Sets sequence = 1
@@ -125,7 +125,7 @@ integrates it into the spanning tree.
 
 ```
 Existing tree structure:
-        A (root, smallest node_id)
+        A (root, smallest node_addr)
        /|\
       C D E
 
@@ -157,8 +157,8 @@ B receives D's TreeAnnounce:
 │   └── TreeState_B = { (B, parent=B, seq=1), (D, parent=A, seq=47), (A, parent=A, seq=203) }
 │
 ├── Evaluates root:
-│   └── Compares node_id_A vs node_id_B
-│   └── If A < B: Root_B = A (A has smaller node_id)
+│   └── Compares node_addr_A vs node_addr_B
+│   └── If A < B: Root_B = A (A has smaller node_addr)
 │
 └── Evaluates parent selection:
     └── Only peer is D
@@ -195,7 +195,7 @@ D receives and merges:
 **T5: D updates its bloom filter**:
 
 ```
-D adds B's node_id to its bloom filter
+D adds B's node_addr to its bloom filter
 D sends FilterAnnounce to parent A
 
 A merges D's bloom filter with its view of D's subtree
@@ -241,7 +241,7 @@ each node only knows its own ancestry and peers. Convergence means:
 
 When multiple isolated nodes connect simultaneously, the network must:
 
-1. Elect a single root (determined by smallest node_id)
+1. Elect a single root (determined by smallest node_addr)
 2. Form a loop-free tree structure
 3. Propagate ancestry information along peer links
 
@@ -250,7 +250,7 @@ When multiple isolated nodes connect simultaneously, the network must:
 ```
 T0: Nodes A, B, C start isolated
     Each is its own root
-    node_id ordering: A < B < C
+    node_addr ordering: A < B < C
 
 T1: Links form: A ←→ B, B ←→ C
 
@@ -301,7 +301,7 @@ depth D with gossip interval G:
 
 **No coordination required**: Convergence emerges from:
 
-- Deterministic root election (smallest node_id)
+- Deterministic root election (smallest node_addr)
 - Deterministic merge rules (highest sequence wins)
 - Eventually consistent gossip
 
@@ -420,7 +420,7 @@ Link C ←→ D fails:
 
 After:
     Partition 1: A ← B ← C
-    Partition 2: D ← E (or E ← D, depending on node_ids)
+    Partition 2: D ← E (or E ← D, depending on node_addrs)
 ```
 
 ### Partition Detection
@@ -455,7 +455,7 @@ Partition 1 (nodes A, B, C):
 Partition 2 (nodes D, E):
 ├── Previous root A is unreachable
 ├── D and E exchange announcements
-├── New root = min(node_id_D, node_id_E)
+├── New root = min(node_addr_D, node_addr_E)
 ├── Tree forms between D and E
 └── Routing works within partition
 ```
@@ -489,10 +489,10 @@ T4: Merged network
 ### Root Stability Across Partitions
 
 A key design consideration: the root should be stable to minimize reconvergence.
-If partition 2 elected a "temporary" root with a large node_id, healing is cheap—
+If partition 2 elected a "temporary" root with a large node_addr, healing is cheap—
 that root immediately defers to the global root.
 
-If by chance partition 2's root has a smaller node_id than partition 1's root,
+If by chance partition 2's root has a smaller node_addr than partition 1's root,
 healing causes partition 1 to reconverge to the new global root.
 
 ---
@@ -837,7 +837,7 @@ Physical topology (full mesh via switch):
     │╱   ╲│
     D ──── C ──── E
 
-node_id ordering: A < C < B < E < D
+node_addr ordering: A < C < B < E < D
 ```
 
 **Tree formation**:
@@ -911,7 +911,7 @@ Physical topology:
       (DSL)     (fiber)
       1 Mbps
 
-node_id ordering: B < A < D < E < C
+node_addr ordering: B < A < D < E < C
 ```
 
 **Cost calculation** (using bandwidth as primary):
@@ -928,7 +928,7 @@ A ~ C: cost = 100000 (9600 bps)
 **Tree formation with costs**:
 
 ```
-Root = B (smallest node_id)
+Root = B (smallest node_addr)
 
 Parent selection:
 ├── A: peers are B (cost 1), C (cost 100000)
@@ -982,7 +982,7 @@ A ─── B ──────────────────────
       │                                   │
       C                                   G
 
-node_id ordering: A < E < B < F < C < G
+node_addr ordering: A < E < B < F < C < G
 ```
 
 **Normal operation**:
@@ -1014,7 +1014,7 @@ T3: Site 2 state:
     E loses path to A
     E evaluates remaining peers: F
     F has no path to A either
-    E compares: node_id_E < node_id_F
+    E compares: node_addr_E < node_addr_F
     E becomes new root for Site 2
 
 T4: Site 2 reconverges:
@@ -1033,7 +1033,7 @@ T5: WAN link restored
 
 T6: E receives B's announcement:
     B's ancestry: [A, B]
-    E learns: A exists, node_id_A < node_id_E
+    E learns: A exists, node_addr_A < node_addr_E
     E adopts A as root
     E selects B as parent
 
@@ -1064,7 +1064,7 @@ initial exchange).
 The gossip-based spanning tree protocol achieves distributed coordination
 through:
 
-1. **Deterministic root election** - Smallest node_id, no negotiation needed
+1. **Deterministic root election** - Smallest node_addr, no negotiation needed
 2. **Local parent selection** - Each node independently chooses best path to root
 3. **CRDT merge semantics** - Conflicts resolved by sequence number, then timestamp
 4. **Bounded state** - O(peers × depth) entries per node, not O(network size)